#include <iostream>
//reference can be used us member of class


class A
{
public:
	double &_a;
	A(double &a):_a(a){};
};




int main()
{	
	double tmp = 6.2;
	A a(tmp);
	std::cout << a._a << std::endl;
	a._a = 10;
	std::cout << tmp << std::endl;
	std::cout << sizeof(a) << std::endl;
	std::cout << sizeof(double) << std::endl;

	return 0;
}
